Re: [Qemu-devel] Why is SeaBIOS used with -kernel?

[Richard W.M. Jones]

On Fri, Apr 01, 2016 at 01:07:55PM +0200, Gerd Hoffmann wrote:
> On Fr, 2016-04-01 at 11:17 +0100, Richard W.M. Jones wrote:
> > On Fri, Apr 01, 2016 at 11:18:30AM +0200, Gerd Hoffmann wrote:
> > >   Hi,
> > > 
> > > > I wonder how we can make use of this in qemu and downstream distros?
> > > > Can we have a bios-min.bin which is used with -kernel boots?
> > > 
> > > We already build two seabios roms: one full featued and one slightly
> > > stripped down to keep it below 128k, for backward compatibility with old
> > > machine types.
> > > 
> > > Adding a third config for -kernel boot should be easy.  For that use
> > > case we can probably also turn on seabios logging to the serial console
> > > and drop sgabios.  We don't need input (no boot menu) and we also don't
> > > need to hook into int10 (no grub/ipxe using that for output).
> > 
> > SeaBIOS logging is slow (or more likely, serial output is slow).
> > And sgabios is useful for debugging.
> 
> Ah, I see.  debuglevel=1 prints too much and debuglevel=0 has no logging
> at all.  We'd need seabios log at least the version banner to serial
> even with debuglevel=0 to replace sgabios.
> 
> https://www.kraxel.org/cgit/qemu/log/?h=work/stripped-seabios
> 
> Not hooked into -kernel yet, so you have to use "-bios bios-kboot.bin".
> 
> Comments?

I think we were working on the same thing ...  Attached is my
version.

Note that you must enable at least CONFIG_MPTABLE else virtio-scsi
does not work in the guest.  I also enabled ACPI & SMBIOS & PIRTABLE.

Rich.

-- 
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0001-bios-Add-fast-variant-of-SeaBIOS-for-use-with-kernel.patch
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